With reference to 'Work', consider the following statements: 1. Work is a vector quantity having both magnitude and direction. 2. If the displacement of an object is zero, the work done by any force acting on it is zero. 3. Work done by gravity on an object moving horizontally is zero. Which of the statements given above is/are correct?

Correct Option The correct option is 2 and 3 only. Explanation In physics, work is defined as the scalar product of force and displacement, and it depends on the component of force acting in the direction of displacement. Statement-wise Analysis - Statement 1: Incorrect. Work is a scalar quantity. It has magnitude only and no direction, as it is defined using the dot product of force and displacement. - Statement 2: Correct. If the displacement of an object is zero, the work done by any force is zero because work depends directly on displacement. - Statement 3: Correct. When an object moves horizontally, the force due to gravity acts vertically downward, making the angle between force and displacement 90°, resulting in zero work done. Key Takeaway: Work is a scalar quantity and is done only when a force has a component along the direction of displacement.

With reference to 'Work', consider the… - NCERT Class 9 Science MCQ

NCERT Class 9 Science — Chapter 4: Work and energy

mcqmedium

With reference to 'Work', consider the following statements:

Work is a vector quantity having both magnitude and direction.
If the displacement of an object is zero, the work done by any force acting on it is zero.
Work done by gravity on an object moving horizontally is zero.

Which of the statements given above is/are correct?

NCERT textbook question

From NCERT Science - class 9 · Page 114

Options

A1 and 2 only
B2 only
C2 and 3 only
D1, 2 and 3

Did you get this right?

Solution

Correct Option

The correct option is 2 and 3 only.

Explanation

In physics, work is defined as the scalar product of force and displacement, and it depends on the component of force acting in the direction of displacement.

Statement-wise Analysis

Statement 1: Incorrect. Work is a scalar quantity. It has magnitude only and no direction, as it is defined using the dot product of force and displacement.
Statement 2: Correct. If the displacement of an object is zero, the work done by any force is zero because work depends directly on displacement.
Statement 3: Correct. When an object moves horizontally, the force due to gravity acts vertically downward, making the angle between force and displacement 90°, resulting in zero work done.

Key Takeaway: Work is a scalar quantity and is done only when a force has a component along the direction of displacement.

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More from Chapter 4: Work and energy

A car and a truck are moving with the same velocity. If the truck is four times as massive as the car, how does the kinetic energy of the truck compare to that of the car?

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Which one of the following is the correct relationship between the commercial unit of energy (kWh) and the SI unit of energy (Joule)?

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When an object is dropped from a certain height, what form of energy does it possess at the midpoint of its fall?

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With reference to the nature of work done, consider the following statements: 1. Work done is negative when the force acts in the direction of displacement. 2. Work done is negative when the force acts opposite to the direction of displacement. 3. Work done is maximum when the force acts perpendicular to the displacement. Which of the statements given above is/are correct?

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Consider an object raised to a height $h$. The gravitational potential energy gained by the object depends on: 1. The volume of the object. 2. The height to which it is raised. 3. The acceleration due to gravity at that place. Which of the statements given above is/are correct?

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